Carb needle

[motomartin]

Two questions
The pump nozzle needle (#28 on the parts diagram) does in basically just drop in with nothing on top of it?
How much difference does the needle make? (hopefully some mind range smoothing)

Thanks,
Martin

[wayne]

It just drops into that jet. Nothing on top.

As for what difference, I can't tell you. Sounds like another geek project for me. Ride with and without.

[CanAm]

Anyone come across carby kits?

[hudson]

Just my two cents on the purpose of the #28 needle in the tube leading to the accelerator pump discharge nozzle. I believe it is there to reduce the volume inside this tube. The discharge hole at the bottom of the tube is very small and would be very difficult to have manufactured a hole this small the length of the tube and impossible to clean if it became gummed or plugged. The reduced diameter at bottom of the needle is there as to not impede flow at discharge hole, the top reduced diameter is so it can not be installed upside down. The only driveability function would be if under certain scenarios such as long highway speed riding the tube maybe drawn empty from the constant high air flow then some of the pump capacity would be needed to refill the tube before it could discharge fuel to the engine during the next throttle opening. I think that under most riding situations it would be impossible to tell if the needle was installed or not. Of course this is just my opinion as I can't confirm any of this with the engineer that designed it. As for the midrange lean stumble that most of these carbs. seem to develop even after being cleaned and proper cable adjustment, I am still working on that and may know something soon. As for carb. kits all of the parts are out there, and with a couple of trips around the planet can be gathered.
Maybe it would be worth while to assemble all of these into kits.

Brian

[Jess]

I made a gasket kit. It does not have the diaphragms.

Best,

[CanAm]

Hi Jess,
That's great news. I haven't pulled mine apart yet so hoping it is not the diaphragm.
What do you charge for the kit?
Cheers,
Seth

[hudson]

Jess,
Which gaskets ? Any other parts in the kit ?

Brian

[Jess]

Gaskets:

13251-37010. Float chamber cap
13277-37010 gasket pilot screw body
13467-37010 gasket enrichment
13460-37010 diaphragm Assy enrichment **** this part is not listed separately in the parts book**** Mine is just the diaphragm not the housing as well.
13419-31210 gasket secondary main jet plug
13249-31210 gasket primary main jet plug
13294-28010 o ring primary pilot jet
13295-37010 o ring unloader
13125-37001 gasket carburetor
13879-37000 gasket air horn

Price for kit is 50.00 plus shipping. Feel free to email me to order at [e-mail]

If you aren’t happy with the kit... RETURN it for a refund... simple

Best,

[HGH 770N]

Good explanation Brian ,
The needle in tube reduces the tube size and therefore increases the pressure of fuel pumped from the diaphragm.
With out needle the spray out of the single hole/jet down the throat of carb would not be good.
On a similar note , if the float bowl gasket has not a good supple tight seal the fuel can get pumped through the gasket face into air passages or out side carb body that is usually visible and a good telltale sign of failure without removing.
Also if the gasket has gone hard and distorted that sits above the needle can prevent the flow between the gap from the oneway jet to the needle jet .
I have successfully replaced several of the needle jet.
As mentioned before on this site , the Jet is not meant to be a replacement part and is quite often chewed up when owners try and remove it .

[motomartin]

Thank you for the information guys.
I think I'll order one of Jess' carb gasket kits before taking it apart to put the needle in.
I think the non-removable jet is also somewhat chewed from attempted removal.
I'm also still running the bike with the ziptie carb bodge rather that it working on a vacuum.